Lumbar Spine MRI: Missed Opportunities for Abdominal Aortic Aneurysm Detection

PurposeThe US Preventive Services Task Force (USPSTF) recommends 1-time sonographic screening for abdominal aortic aneurysms (AAAs) in male smokers ages 65-75 and other selected individuals in this age group based on risk factors. Patients in this age range are frequent utilizers of lumbar spine MRI, in which the abdominal aorta is typically fully imaged. The purpose of this study was to assess the potential detection rate of AAAs on lumbar spine MRI performed in the USPSTF screening age range with systematic aortic measurement and the frequency with which AAAs are currently reported in practice.Materials and MethodsAll consecutive lumbar spine MRI exams performed without contrast at a single academic tertiary care center over a 1-year period (4/1/2016-3/31/2017) in patients ages 65-75 were retrospectively reviewed. Maximal anteroposterior, and transverse dimensions of the abdominal aorta were measured using axial T2-weighted images, supplemented with sagittal T2-weighted images if assessment was limited by field-of-view or artifact. The detection rate of AAA, defined as dilation of the aorta to a diameter of ≥3 cm, size of AAAs detected, and frequency with which AAAs were reported, were assessed. Differences in aortic diameters and aneurysm detection rates between genders were compared with the unpaired 2-sample t test.ResultsThree hundred and ninety-five lumbar spine MRIs were reviewed, 240 (60.8%) in women and 155 (39.2%) in men, with mean ± standard deviation (SD) age of 70.2 ± 3.2 years. AAAs were detected in 38/395 (9.6%) cases, most (33/38, 86.8%) of which were <4 cm. Of these, only 4 (10.5%) were reported by the interpreting radiologist; 3/4 (75%) corresponded to aneurysms ≥4 cm.ConclusionLumbar spine MRI performed in the USPSTF AAA screening age range, especially in men, facilitates frequent detection of AAA when the aorta is systematically measured. However, in typical lumbar spine assessment, AAAs are often underreported, particularly for smaller aneurysms.     

Sealing of type III endoleaks with ethylene vinyl alcohol copolymer in a canine model

PURPOSE: To test ethylene vinyl alcohol copolymer (EVOH) as a sealing agent for persistent abdominal aortic aneurysm (AAA) endograft leaks. MATERIALS AND METHODS: Twelve dogs underwent creation of AAAs with a Palmaz P4014 stent. A 10-mm x 5-cm Wallgraft endoprosthesis with a 4-mm-diameter hole cut into its side was deployed within the AAA. One week later, computed tomography (CT) and angiography were performed and the aneurysm sac was catheterized through the 4-mm hole. Then, EVOH was injected into the sac and lumbar arteries. Four weeks thereafter, all surviving animals underwent repeat CT scanning and angiography and were then euthanized. The AAA underwent gross and microscopic study. RESULTS: Three dogs died from aortic rupture within 24 hours of AAA creation and the remaining nine dogs survived to receive EVOH. All nine dogs had persistent flow into the sac and lumbar arteries at the time of EVOH delivery. Seven dogs survived to the end of the experiment, and all aneurysm sacs and lumbar arteries remained occluded on angiography and CT. Histologic examination revealed EVOH and thrombus admixed, with thrombus in varying stages of organization filling the aneurysm sac and lumbar arteries. CONCLUSIONS: Embolization of type III endoleaks with EVOH proved to be feasible in a canine model. Further work is warranted to determine its therapeutic utility.     

3D segmentation of abdominal aorta from CT-scan and MR images

We designed a generic method for segmenting the aneurismal sac of an abdominal aortic aneurysm (AAA) both from multi-slice MR and CT-scan examinations. It is a semi-automatic method requiring little human intervention and based on graph cut theory to segment the lumen interface and the aortic wall of AAAs. Our segmentation method works independently on MRI and CT-scan volumes and has been tested on a 44 patient dataset and 10 synthetic images. Segmentation and maximum diameter estimation were compared to manual tracing from 4 experts. An inter-observer study was performed in order to measure the variability range of a human observer. Based on three metrics (the maximum aortic diameter, the volume overlap and the Hausdorff distance) the variability of the results obtained by our method is shown to be similar to that of a human operator, both for the lumen interface and the aortic wall. As will be shown, the average distance obtained with our method is less than one standard deviation away from each expert, both for healthy subjects and for patients with AAA. Our semi-automatic method provides reliable contours of the abdominal aorta from CT-scan or MRI, allowing rapid and reproducible evaluations of AAA.     

Cost identification of abdominal aortic aneurysm imaging by using time and motion analyses

PURPOSE: To compare the costs of performing helical computed tomographic (CT) angiography with three-dimensional rendering versus intraarterial digital subtraction angiography (DSA) for preoperative imaging of abdominal aortic aneurysms (AAAs). MATERIALS AND METHODS: A single observer determined the variable direct costs of performing nine intraarterial DSA and 10 CT angiographic examinations in age- and general health-matched patients with AAA by using time and motion analyses. All personnel directly involved in the cases were tracked, and the involvement times were recorded to the nearest minute. All material items used during the procedures were recorded. The cost of labor was determined from personnel reimbursement data, and the cost of materials, from vendor pricing. The variable direct costs of laboratory tests and using the ambulatory treatment unit for postprocedural monitoring, as well as all fixed direct costs, were assessed from hospital accounting records. The total costs were determined for each procedure and compared by using the Student t test and calculating the CIs. RESULTS: The mean total direct cost of intraarterial DSA (+/- SD) was $1,052 +/- 71, and that of CT angiography was $300 +/- 30, which are significantly different (P < 4.1 x 10(-11)). With 95% confidence, intraarterial DSA cost 3.2-3.7 times more than CT angiography for the assessment of AAA. CONCLUSION: Assuming equal diagnostic utility and procedure-related morbidity, institutions may have substantial cost savings whenever CT angiography can replace intraarterial DSA for imaging AAAs.     

Endoluminal Treatment of Ruptured Abdominal Aortic Aneurysm with Small Intestinal Submucosa Sandwich Endografts: A Pilot Study in Sheep

Purpose: To evaluate efficacy of small intestinal submucosa (SIS) Sandwich endografts for the treatment of acute rupture of abdominal aortic aneurysms (AAA) and to explore the short-term reaction of the aorta to this material. Methods: In eight adult sheep, an infrarenal AAA was created transluminally by dilation of a short Palmaz stent. In six sheep, the aneurysm was then ruptured by overdilation of the stent with a large angioplasty balloon. Two sheep with AAAs that were not ruptured served as controls. A SIS Sandwich endograft, consisting of a Z stent frame with 5 bodies and covered inside and out with SIS, was used to exclude the ruptured and non-ruptured AAAs. Follow-up aortography was done immediately after the procedure and before sacrifice at 4, 8, or 12 weeks. Autopsy and histologic studies followed. Results: Endograft placement was successful in all eight sheep. Both ruptured and non-ruptured AAAs were successfully excluded. Three animals with AAA rupture developed hind leg paralysis due to compromise of the arterial supply to the lower spinal cord and were sacrificed 1 day after the procedure. In five animals, three with rupture and two controls, follow-up aortograms revealed no aortic stenoses and no perigraft leaks. Gross and histologic studies revealed incorporation of the endografts into the aortic wall with replacement of SIS by dense neointima that was completely endothelialized in areas where the endograft was in direct contact with the aortic wall. In central portions of the endograft, in contact with the thrombosed aneurysm, endothelialization was incomplete even at 12 weeks. Conclusion: The SIS Sandwich endografts effectively excluded simple AAAs and ruptured AAAs. They were rapidly incorporated into the aortic wall. A detailed long-term study is warranted.     

Endovascular stent-graft in abdominal aortic aneurysms: the relationship between patent vessels that arise from the aneurysmal sac and early endoleak

PURPOSE: To determine the association of patent sac branch vessels (lumbar and inferior mesenteric arteries [IMAs]) with early endoleak rate after stent-graft repair of abdominal aortic aneurysm (AAA). MATERIALS AND METHODS: Pre- and postoperative computed tomographic (CT) angiograms in 158 patients who underwent stent-graft AAA repair were retrospectively reviewed to determine the preoperative patency of IMAs and other sac branch vessels (feeders) and presence or absence of immediate postoperative endoleak. Relationships of early endoleak rate with total branch vessel, IMA, and lumbar artery patency and graft type were evaluated. RESULTS: There was a significant association between patency of sac feeders and rate of early endoleak, especially type 2. As total patent feeders increased from zero to three to four to six, total endoleak rate increased from 6% (one of 17) to 35% (30 of 86); type 2 endoleak rate, from 0% to 25%. IMA patency was significantly associated with total early endoleak rate. Increasing lumbar artery patency also was associated with significantly higher total and type 2 endoleak rates: With zero to three lumbar arteries, the total endoleak rate was 17% and type 2 endoleak rate was 13%, as compared with 60% and 50%, respectively, with more than six patent lumbar arteries. CONCLUSION: Sac branch vessel patency is associated with significantly higher early total and type 2 endoleak rates after stent-graft repair of AAAs; thus, patent sac branches play an important role in the pathogenesis of endoleaks.     

Twin-tube endografts for aortic aneurysms: an experimental feasibility study.

PURPOSE: To explore feasibility of twin-tube endografts (TTEGs) for treatment of abdominal aortic aneurysm (AAA). MATERIALS AND METHODS: AAAs were created in six dogs by overdilation of Palmaz stents. TTEGs made of seven 9.5-mm-diameter Gianturco R?sch Z (GRZ) stents and covered with PTFE were deployed simultaneously from both femoral arteries through 10-F sheaths to exclude the AAA. Follow-up aortography was performed immediately and at 2, 4, and 8 weeks. Two dogs were killed at 4 weeks and four were killed at 8 weeks. Gross and histologic examinations were performed. RESULTS: AAA creation and TTEG placement were successful in all six dogs. TTEGs completely excluded AAAs in five dogs. Minor temporary perigraft leak was seen in one dog immediately after stent placement. Four dogs had TTEGs patent to termination at 8 weeks. In two dogs with oversized TTEGs, one of the twin endografts occluded at 2 weeks. At autopsy, TTEGs were formed in semicircular shape and histology did not show any significant inflammatory reaction. CONCLUSION: TTEGs show promise for treatment of AAA, with the potential of reducing the introductory sheath size. Further experimental studies, particularly with TTEGs extended into iliac arteries, are warranted.     

Aortic-neck dilation after endovascular abdominal aortic aneurysm repair (EVAR): can it be predicted?

Purpose

This study was performed to evaluate whether dynamic computed tomography (CT) can provide functional vessel information predicting outcomes of aortic neck in patients undergoing endovascular aneurysm repair (EVAR) of an abdominal aortic aneurysm (AAA).

Materials and methods

Twenty patients with and 20 without AAA were enrolled. Electrocardiographically (ECG)-gated data sets were acquired with a 64-slice CT scanner. Axial pulsatility measurements were taken at three levels: 2 cm above the highest renal artery; immediately below the lowest renal artery; 1 cm below the lowest renal artery. Three independent readers performed the measurements. Systolic and diastolic blood pressures were measured in the brachial artery to calculate arterial-wall distensibility expressed as pressure strain elastic modulus (Ep). Cross-sectional area change, wall distensibility and Ep value were statistically compared.

Results

No significant differences were found in terms of Ep values in the suprarenal and juxtarenal level. In the AAA group, a significantly higher value was obtained at the infrarenal level. A subgroup of patients with AAA (45%) had a significantly higher Ep value at the infrarenal level.

Conclusions

Dynamic CT provided insight into the abdominal aorta pathophysiology. Identifying patients with higher infrarenal distensibility could change selection of graft size to improve proximal fixation.     

A ruptured mycotic aortic aneurysm in a patient with urinary retention: A case report

Symptomatic abdominal aortic aneurysm (AAA) is a diagnosis that is a true emergency. Since AAAs are typically asymptomatic prior to rupturing, they can easily be missed. When an abdominal aortic aneurysm becomes symptomatic and ruptures, the ramifications can be catastrophic for the patient. We present a case of a 55-year-old male who presented with urinary retention and suprapubic pain. Computerized tomography demonstrated a rapidly expanding AAA and signs of impending rupture. Emergent vascular surgical repair was performed successfully. There was concern for mycotic nature of the AAA with recent COVID-19 infection and possible bacteremia. This case demonstrates the need for maintaining a wider differential when examining patients and avoiding anchoring bias and serves as a point of discussion for potential complications of COVID-19 infection.     

Measurement of trabecular bone mineral density in the thoracic spine using cardiac gated quantitative computed tomography

OBJECTIVES: To develop a method and evaluate the performance of thoracic bone mineral density (BMD) measurement using cardiac gated quantitative computed tomography (QCT). METHODS: A total of 762 participants (57% female) with a mean age of 61 years had a CT examination of the heart using prospective cardiac gating. A subset of 443 participants had replicate CT examinations of the heart. Another, nonindependent subset of 464 participants had CT examination of the abdomen. A QCT calibration phantom was included in all scans. Trabecular BMD was measured in the thoracic (T6-T11) and lumbar (T11-L4) spine. Tests of calibration and refinement and simple correlations between replicate thoracic BMD measurements and between thoracic and lumbar BMD measurements were calculated. RESULTS: There was high correlation between replicated thoracic BMD measurements in men (r = 0.995, P < 0.0001) and in women (r = 0.995, P < 0.0001). There was high correlation between thoracic and lumbar BMD in men (r = 0.90, P < 0.0001) and in women (r = 0.94, P < 0.0001). The mean BMD was higher in the thoracic spine than the lumbar spine in men (137.58 mg/cm3 vs. 126.94 mg/cm3, P < 0.0001) and in women (152.07 mg/cm3 vs. 133.44 mg/cm3, P < 0.0001). In both genders, thoracic and lumbar BMD was inversely associated with age (all P < 0.05). CONCLUSIONS: Cardiac gated CT, primarily intended for measurement of coronary vascular calcium, can be used to measure thoracic BMD with high precision. Thoracic BMD measurements using this method are highly correlated with QCT measurements in the lumbar spine.     

Estimation of Abdominal Aortic Aneurysm Rupture Risk with Biomechanical Imaging Markers

PurposeTo evaluate whether the biomechanical marker known as rupture risk equivalent diameter (RRED) was superior to the actual abdominal aortic aneurysm (AAA) diameter in estimating future rupture risk in patients who had undergone pre-rupture computed tomography (CT) angiography.Materials and MethodsA retrospective study was conducted in 13 patients with ruptured AAAs who had undergone CT angiography before and after rupture between 2001 and 2015. The median time between the 2 scans was 731 days. Biomechanical and geometrical markers such as maximal AAA diameter, peak wall stress (PWS), and RRED were calculated with AAA-dedicated software. The main analyses determined whether RRED was higher than the actual diameter and the threshold diameter for elective surgery (55 mm for men, 50 mm for women) in AAAs before and after rupture. Differences between diameter and biomechanical markers before and after rupture were tested with appropriate statistical tests.ResultsRRED before and after rupture was smaller than the actual diameter in 7 of 13 cases. Post-rupture RRED was estimated to be smaller than the threshold diameter for elective repair in 4 cases, again suggesting a low rupture risk. The median PWS before and after rupture was 181.7 kPa (interquartile range [IQR], 152.1–244.2 kPa) and 274.1 kPa (IQR, 172.2–377.2 kPa), respectively.ConclusionsRRED was smaller than the actual diameter in more than half of pre-rupture AAAs, suggesting a lower rupture risk than estimated with the actual diameter. The results suggest that the currently available biomechanical imaging markers might not be ready for use in clinical practice.     

Effect of aortic sclerosis on bone mineral measurements by dual-photon absorptiometry

Measurements of the bone mineral content (BMC) of lumbar spine by dual-photon absorptiometry (DPA) are performed mainly in the anteroposterior (AP) projection. Due to superimposition of the abdominal aorta, the BMC measured for patients with aortic calcification usually is too high. To determine the influence of aortic calcifications, DPA scans were performed in the AP-projection on 100 dissected abdominal aortae with different degrees of atherosclerosis placed on a human lumbar spine cast in lucite. The measured values were compared with those obtained in the same projection without the aortae. The average increase of the BMC values relative to the mean for the vertebrae L2 to L4 for aortae with severe complicated lesions, i.e., those containing larger amounts of calcium, was 0.03 g/cm2, with a maximum deviation of 0.09 g/cm2. Aortae with fatty streaks or fibrous plaques did not cause significant increases of the BMC. The mean deviation for aortae with mild complicated lesions, i.e., those containing smaller amounts of calcium, was within the range of instrument precision.     

腔内隔绝术治疗腹主动脉瘤(附2例报告)

目的：探讨腔内隔绝术治疗腹主动脉瘤（AAA）的方法、疗效、并发症及存在的问题。方法：2例高龄、多病并存的AAA患者在全订及动脉造影的监控下，植入血管内支架－聚酯移植物复合体，对AAA进行腔内隔绝术。结果：术后定期复查彩超、CT及血管造影显示支架通畅，无移位、扭曲、支架外壁与瘤腔间充满血栓，未发现搏动的肠系膜下动脉及腰动脉，未发现渗漏。AAA外径无变化。患者腹部搏动性肿块消失。结论：腔内隔绝术治疗AAA避免了外科手术的各种缺点，具有简便、安全、疗效确定等优点。     

Evaluation of blunt abdominal trauma using PACS-based 2D and 3D MDCT reformations of the lumbar spine and pelvis

OBJECTIVE: The purpose of this study was to show the value of 2D and 3D reformations of CT data from abdominal and pelvic CT performed immediately at the workstation using a PACS-based software program to evaluate the lumbar spine and pelvis in patients with blunt abdominal trauma. MATERIALS AND METHODS: We reviewed the abdominopelvic CT scans and conventional radiographs of the lumbar spine or pelvis of 156 consecutive patients with blunt abdominal trauma. The CT data were compared with the radiographic findings and also with the findings of dedicated repeat CT of the spine or pelvis, when performed. RESULTS: CT depicted 80 fractures of the lumbar spine and 178 pelvic fractures. Radiography showed 40 fractures of the lumbar spine and 138 pelvic fractures. No additional fractures were identified on dedicated repeat CT. CONCLUSION: Conventional radiographs to clear the lumbar spine are no longer required when abdominopelvic CT data are available. CT and reformatted CT data show more fractures than radiography and miss no fractures compared with dedicated CT of the lumbar spine or pelvis. Having these images immediately available through the PACS workstation saves time for the trauma team in the management of critically ill patients.     

Endovascular abdominal aortic aneurysm repair: how many patients are eligible for endovascular repair?

PURPOSE: The purpose of this study was to determine how many patients with abdominal aortic aneurysm (AAA) are eligible for endovascular abdominal aortic aneurysm repair (EVAR). MATERIALS AND METHODS: We retrospectively reviewed computed tomography (CT) angiograms obtained between January 2002 and June 2003 in 182 patients with suspected AAA. Indication for surgical or endovascular treatment was based on clinical and radiological criteria. The percentage of patients eligible for EVAR was evaluated. RESULTS: Out of a total of 182 patients with suspected AAA studied by CT angiography, after combined radiological-surgical assessment, 130 were considered eligible for surgical or endovascular treatment (71.4%). EVAR was indicated in 51 patients (39.3%, group A) and surgical repair was indicated in 79 patients (60.7%, group B). The reasons for ineligibility for EVAR were the following: unfavourable anatomy of the proximal neck in 41 patients (51.9%), diameter of the aneurysm sac >7 cm in 13 patients (16.4%), markedly tortuous/dilated iliac axis in six patients (7.6%), age <65 years in 17 patients (21.5%) and patient refusal in two cases (2.5%). There were no statistically significant differences in aneurysm diameter (52.7+/-0.8 versus 49.8+/-1.2 mm, p=ns), patients' age (73.2+/-1.2 versus 70.6+/-2.02 years, p=ns) or proximal neck length (2.95+/-1 versus 3.03+/-1.2 cm, p=ns) between groups A and B. CONCLUSIONS: Endovascular repair of abdominal aortic aneurysms through the placement of aortic stent-grafts has now become a viable alternative to open surgery. In recent years, the number of patients treated with EVAR has steadily risen as a result of increased physician experience, availability of new and more versatile devices and improvements in noninvasive imaging techniques. Unfavourable neck anatomy is the primary factor for exclusion from endovascular repair.     

腹主动脉瘤附壁血栓分布规律和相关因素分析

目的:研究腹主动脉瘤(AAA)附壁血栓(ILT)的生长规律,探讨ILT与年龄、性别、AAA直径的关系。方法:对103例AAA连续病例行CT扫描,观察有无ILT及ILT的分布规律,测量AAA直径和ILT最大厚度,分析ILT与年龄、性别及动脉瘤大小的关系。结果:66．9％AAA有ILT,女性AAA有ILT较少见(15．4%)。ILT与AAA直径、患者年龄相关,AAA直径小于40mm时形成ILT的比例为21．4％,年龄小于60岁时形成ILT的比例为25．0％。以近端瘤颈截面的中心和髂动脉分叉做一连线,血栓总是分布在距离该轴线较远的瘤壁。结论瘤体内血流可能是ILT形成的重要因素;女性和年龄小于60岁不易形成血栓,提示ILT的形成是多因素的。     

Radiologic features and anatomic basis of atypical clinical presentations of ruptured abdominal aortic aneurysms

Ruptured abdominal aortic aneurysms (AAAs) occasionally manifest with atypical clinical presentations and can be initially misdiagnosed. Symptoms are attributable either to local mass effect from the aneurysm or a contained rupture, or to the particular cavity or anatomic space into which an aneurysm bleeds. Radiologic studies obtained in this patient population often will demonstrate signs of the ruptured AAA, and these signs should be actively searched for when a ruptured AAA can be in the differential diagnosis. Emergent computed tomographic examination is indicated to confirm any clinical or radiologic suspicion of a ruptured abdominal aortic aneurysm, provided that the patient remains hemodynamically stable. The anatomic basis for a ruptured AAA presenting clinically as renal colic is discussed and illustrated, and the spectrum of clinical presentations of ruptured AAAs is reviewed.     

Unjustified CT examinations in young patients

The doses of radiation from computed tomography (CT) are relatively high, yet CT is being increasingly utilized. Furthermore, the radiation-induced lifetime risk of cancer mortality is higher at younger age. The purpose of this study was to find out whether previous CT examinations done on patients aged under 35 years were justified, and if not, whether there would have been other, more justifiable imaging modalities available. Fifty CT examinations of the head and 30 CT examinations each of the lumbar spine, cervical spine, abdomen, nasal sinuses and trauma were evaluated consecutively since the beginning of the year 2005 by using electronic patient files, the referral guidelines for imaging recommended by the European Commission and certain principles of classification. Seventy-seven per cent of the CT examinations of the lumbar spine, 36% of the head, 37% of the abdomen, 20% of the nasal sinuses and 3% of the cervical spine were unjustified. Most of these unjustified examinations could have been replaced by magnetic resonance imaging. In order to reduce utilization of ionizing radiation, both the referring practitioner and the radiologist responsible for the examination should carefully consider the justification for CT examinations and the possibility of using other imaging modalities.     

Value of volume measurements in evaluating abdominal aortic aneurysms growth rate and need for surgical treatment

Purpose

To examine whether indices other than the traditionally used abdominal aortic aneurysm (AAA) maximum diameter, such as AAA volume, intraluminal thrombus (ILT) thickness and ILT volume, may be superior to evaluate aneurismal enlargement.

Materials and methods

Thirty-four small AAAs (initially presenting a maximum diameter <5.5 cm which is the threshold for surgical repair) with an initial and a follow-up CT were examined. Median increase and percentile annual change of these variables was calculated. Correlation between growth rates as determined by the new indices under evaluation and those of maximum diameter were assessed.AAAs were divided according to outcome (surveillance vs. elective repair after follow-up which is based on the maximum diameter criterion) and according to growth rate (high vs. low) based on four indices. Contingency between groups of high/low growth rate regarding each of the four indices on one hand and those regarding need for surgical repair on the other was assessed.

Results

A strong correlation between growth rates of maximum diameter and those of AAA and ILT volumes could be established. Evaluation of contingency between groups of outcome and those of growth rate revealed significant associations only for AAA and ILT volumes. Subsequently AAAs with a rapid volumetric increase over time had a likelihood ratio of 10 to be operated compared to those with a slower enlargement. Regarding increase of maximum diameter, likelihood ratio between AAAs with rapid and those with slow expansion was only 3.

Conclusion

Growth rate of aneurysms regarding 3Dimensional indices of AAA and ILT volumes is significantly associated with the need for surgical intervention while the same does not hold for growth rates determined by 2Dimensional indices of maximum diameter and ILT thickness.     

Endovascular abdominal aortic aneurysm repair in 144 patients: correlation of aneurysm size, proximal aortic neck length, and procedure-related complications.

PURPOSE: During endovascular abdominal aortic aneurysm (AAA) repair, larger aneurysms often present formidable anatomic challenges to the insertion of the delivery catheter and graft deployment. The authors sought to evaluate whether large-diameter aneurysms and those with short proximal aortic necks might be associated with a higher frequency of insertion-related and short-term complications. MATERIALS AND METHODS: From October 1999 to August 2000, 144 patients underwent elective endovascular graft placement for infrarenal AAA disease at the authors' institution. These patients were treated with use of the AneuRx bifurcated endoprosthesis. AAA size (maximum aneurysm diameter) and proximal aortic neck length were compared to estimated blood loss, operative time, accuracy of graft placement, presence of endoleak, intraoperative and postoperative complications (such as limb occlusion or vascular injury), length of hospital stay, and mortality. Statistical methods included correlation analysis and logistic regression. RESULTS: There were 121 men and 23 women whose aneurysms ranged in size from 3 cm to 9.8 cm (mean, 5.6 cm; 95% CI, 5.4-5.8 cm). Endograft insertion was successful in all cases. There were three deaths within 30 days (2.1%) and seven deaths overall (4.9%). There were 43 intraoperative complications (29.9%) in 31 patients (21.5%), most of them minor. Patients with major intraoperative complications had significantly longer procedure times than those without complications (337 vs. 149 min; P <.0001). In the postoperative period (within 30 days), 31 complications (21.5%) occurred in 28 patients (19.4%), again most of them minor. AAA size was unrelated in any way to the rate of complications, but short proximal aortic neck length was associated with more serious intraoperative and postoperative complications (P =.0404 and P =.0230, respectively), and decreased 30-day and overall survival (P =.0240 and P =.0152, respectively). CONCLUSIONS: Endovascular repair of large AAAs can be challenging; however, the size of the AAA does not influence the rate of complications. A short proximal aortic neck is the only significant risk factor for more serious complications.